Connecting plate for battery holder and method of producing the same

ABSTRACT

The connecting plates  10, 10 ′ for a battery holder are characterized in that a molded resin plate  11  for integrally molding bus bars  16, 16 ′ for connecting a plurality of batteries A at intervals corresponding to an arrangement of the plurality of batteries incorporates voltage detection terminals  17  for detecting voltages of the desired batteries in such a condition as to be connected to the bus bars.

This is a divisional of application Ser. No. 09/170,211 filed Oct. 13, 1998 the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to connecting plates mounted in a battery holder for containing a number of columnar batteries for use in an electric vehicle or the like and to a method of producing the same.

The present application is based on Japanese Patent Application No. Hei. 9-279257, which is incorporated herein by reference

As a member for connecting plural batteries in series or in parallel, conventionally, a connecting plate 100 shown in FIGS. 25(A) and 25(B) is proposed.

The connecting plate 100 comprises a molded resin board 103 and bus bars 102 which are integrally molded with a resin. The bus bars 102 respectively connect to two batteries 101. In a molded resin board 103 of the connecting plate, a hexagonal window 103 a and a rectangular window 103 b through which electrode holes 102 a at the ends of the batteries 101 are exposed are formed, The two batteries 101 are connected to each other by fastening the bus bars 102 respectively to nut-shaped positive and negative electrodes 101 a and 101 b by bolts 104. Also a ring terminal 105 partially constituting a voltage detection circuit is connected to one of the windows or the hexagonal window 103 a. A fuse case 107 is connected in series to the other end side of an electric wire 106 which is connected at one end to the ring terminal 105. The other end of the electric wire is connected to an ECU which is not shown. A fuse 108 is housed in the fuse case 107. The ends of the fuse are connected to electrical contact portions 109 a of female terminals 109 connected to the electric wire 106, respectively.

FIG. 26 shows another example of a connecting plate of the prior art.

In the connecting plate 100′, plural L-shape bus bars 102, respectively having connecting legs 102 b′ of different lengths are moldingly fixed by a molded resin board 103. One end of each of the connecting legs 102 b′ protrudes from one side edge of the molded resin board 103. Ends on one side of electric wires 106 are welded to the protruding ends, respectively. The other ends of the wires are connected via a fuse case 107′ to an ECU which is not shown.

In the fuse case 108′, two L-shape pressure contact terminals 111 are opposingly disposed on a case substrate 110. The electric wires 106 are welded to basal plates 111 a of the pressure contact terminals 111, respectively. Lead wires 108 a′ of fuses 108 are connected by pressure contact to slots 111 c of pressure contact pieces 111 b upstanding from the basal plates 111 a, respectively.

The connecting plate 100 of FIG. 25 has many connecting portions in one circuit. In the voltage detection circuit, for example, there are six connecting portions indicated by letters a, b, . . . , and f. The number of parts is large. Therefore, there is a fear that the reliability of electrical connection is impaired. Furthermore, a work of fastening bblts must be conducted while holding respective ring terminals 105 one by one by a hand. As the number of electric wires to be connected is larger, therefore, the works of laying and routing the electric wires become more cumbersome and difficult.

By contrast, in the connecting plate 100′ of FIG. 26, the L-shape bus bars 102′ of different dimensions are used. Therefore, the plate has difficulties in cost and production management. In the same manner as the connecting plate 100, the number of parts is large and there are many connecting portions in one circuit (five portions a′, b′, . . . , e′). Moreover, the connecting plate has a problem in that the welding portions between the electric wires 106 and the connecting legs 102 b′ must be protected.

Furthermore, the electric wires 106 for the connecting plates 100 and 100′ are directly connected to the batteries 101, and therefore an adequate protecting structure may be required. However, such protecting structure is complicated since bulky members such as the fuse cases 107 and 108′ are attached to the electric wires 106.

FIG. 27 shows a structure in which batteries for an electric vehicle or the like are directly connected to one another without using connecting plates. In each of rectangular batteries 101′, the positive and negative electrodes 101 a′ and 101 b′ are juxtaposed in one end side. Adjacent batteries are connected to each other by a main power source wire 112. An electric wire 106 (a voltage detection circuit) which has a fuse case 107 in the same manner as FIG. 25 is connected to a required electrode 101 b′.

Also in this case, in the same manner as described above, the number of parts is large (the voltage detection circuit). Since the electric wires have many exposed portions, it is dangerous. Furthermore, the main power source wire 112 and the electric wire 106 of the voltage detection circuit intersect with each other, so that the wiring is complicated. This often causes the wiring to be erroneously conducted.

In the cases of the connecting plates 100, 100′, it may be reasoned to form the connecting electric wire 106 in the molded resin plate 103 by insert molding.

However, a group of electric wires 113 are rigidly secured within a molded resin plate 114 but set free outside by the conventional insert molding as shown in FIG. 28 and this allows stress to be concentrated in the root portion 113 a of the electric wires 113 as the boundary portion. In an extreme case, slight external force acting on the root portion 113 a may result in rupture that portion. In order to prevent this situation, the group of electric wires 113 may be bound with a band 115 for fixing purposes or fixed by providing fixing means in part of or on the periphery of the molded resin plate 114. Even in this case, such work is done after the insert molding operation and it is impossible to eliminate the concentration of stress in the root portion 113 a.

Moreover, one of the factors causing such a rupture to the root portion 113 a of the electric wire 113 is biting in an electric-wire mounting grooves 117 in the exit portion between the top and bottom forces.

In the conventional insert molding of electric wire, molten resin forced into a mold 114 from the nozzle 119 of a molding machine 118 is higher in heat-resistant temperature than the insulating cover of the ordinary electric wire 113 as shown in FIG. 29, which results in raising cost because a heat-resistant electric wire such as what is covered with polyimide resin has to be used.

SUMMARY OF THE INVENTION

It is an object of the present invention made in view of the foregoing problems to provide a connecting plate for a battery holder and a method of producing the connecting plate in which battery-to-battery connecting bus bars and voltage detection terminals forming voltage detection circuits are resin-molded integrally by insert molding to decrease the number of parts exposed outside so that an easy-to-fabricate, safety structure is provided.

It is an another object of the present invention to provide a connecting plate for a battery holder, which connecting plate has a smaller number of component parts and connections and offers excellent reliability of electrical connections and is unlikely to produce errors in battery-to-battery connection and wiring.

It is still another object of the present invention to provide a connecting plate so structured as to prevent stress from being concentrated in a portion where resin-molded connecting electric wires by insert molding are drawn outside.

A further object of the present invention is to provide a method of producing a low-cost connecting plate capable of using ordinary electric wires covered with polyvinyl chloride or polyethylene in place of special heat-resistant electric wires covered with polyimide resin.

Other and further objects of the invention will appear more fully from the following description.

In order to accomplish the aforesaid objects, a connecting plate for a battery holder according to the present invention is characterized in that a molded resin plate for integrally molding bus bars for connecting a plurality of batteries at intervals corresponding to an arrangement of the plurality of batteries incorporates voltage detection terminals for detecting voltages of the desired batteries in such a condition as to be connected to the bus bars.

According to the present invention, a connecting plate for a battery holder of an easy-to-fabricate, safety structure is obtainable wherein the battery-to-battery connecting bus bars and the voltage detection terminals forming voltage detection circuits are resin-molded integrally by insert molding so as to decrease the number of parts exposed outside.

The voltage detection terminal has a superposed contact portion at one end with respect to the bus bar, an electric-wire connecting portion at the other and an device mounting portion for mounting a circuit protective element between one and the other ends thereof; the other end of the electric wire whose one end is connected to the electric-wire connecting portion is led out from the molded resin plate; and the circuit protective element is connected to the device mounting portion.

With this arrangement, the bus bars and the voltage detection terminal are integrally and fixedly connected by insert molding and the connecting electric wire with respect to the voltage detection terminal is sealed up in the molded resin plate, whereby it is possible to provide such a connecting plate for a battery holder as has a smaller number of component parts and connections and offers excellent reliability of electrical connections and is unlikely to produce errors in battery-to-battery connection and wiring.

The molded resin plate according to the present invention is preferably provided with an electric wire holder integrally formed with one side edge of the molded resin plate; and the other end side of the electric wire whose one end is connected to the voltage detection terminal is held by the electric wire holder. Thus, a number of electric wires constituting the connecting plate for a battery holder are bundled and held on one side edge, so that the electric wires are readily connected to any other electrical equipment.

The molded resin plate according to the present invention is preferably provided with a pair of upper and lower elastic mats integrally molded to one side edge of the molded resin plate; and the other end side of the electric wire whose one end is connected to the voltage detection terminal is held by the mats.

According to the present invention, the stress applied to the roots of the group of electric wires drawn outside from the molded resin plate is absorbed and eased by the mats comprising the upper and lower elastic bodies, whereby the electric wires are prevented from being ruptured.

In the device according to the present invention, the molded resin plate has a non-filling portion (a mounting window) vertically opened so that the device mounting portion of the voltage detection terminal is exposed from the connecting plate; and the voltage detection terminal is contained in the non-filling portion.

Consequently, the connecting plate can be replaced from the outside when the circuit protective element is cut by fusing and maintenance is facilitated.

The device mounting portion of the voltage detection terminal according to the present invention has a connecting piece for integrally holding the superposed contact portion and the electric-wire connecting portion; and the connecting piece is cut off in the non-filling portion, the circuit protective element being connected between both ends of the connecting piece.

According to the present invention, a great deal of cost reduction can be anticipated as the number of component parts and that of man-hours are small since the voltage detection terminal can be handled as one part to which the circuit protective element is connected until the connecting piece is cut off.

According to the present invention, window frames for mounting circuit protective elements are preferably formed by providing a wall surrounding the non-filling portion of the molded resin plate; and a pair of element fixing arms corresponding to the window frames are provided.

For example, the circuit protective element is temporarily fixed until it is fixed by soldering with a pair of element fixing arms and this is convenient for storage and transportation and when the circuit protective element is fixed by soldering, it is prevented from dropping out even though the molded resin plate is turned upside down. The soldering work is thus facilitated.

A method, according to the present invention, of producing a connecting plate for a battery holder comprises the steps of:

a) preparing terminal-equipped electric wires by connecting the voltage detection terminal to one end of each of a plurality of electric wires invariable or different in length;

b) arranging the voltage detection terminals of the plurality of terminal-equipped electric wires in conformity with the arranging positions of to be superposed and connected bus bars, wiring a group of electric wires connected to the respective voltage detection terminals so as to be drawn from one side edge of the molded resin plate and binding the electric wires to form a plate harness;

c) preparing a primary molded piece by setting the plate harness thus formed to a primary mold and integrally resin-molding the plate harness excluding the superposed contact portion of the voltage detection terminal;

d) preparing a secondary molded piece by setting the primary molded piece to a second mold, superposing the superposed contact portion of the voltage detection terminal properly on the battery-electrode connecting hole of the bus bars and integrally resin-molding the superposed combination; and

e) cutting the connecting piece of the device mounting portion where the primary molded piece is exposed so as to connect the circuit protective element between both ends of the connecting piece.

Since the bus bars, voltage detection terminals, connecting electric wires and the like are formed by insert molding through two steps; namely, the primary molding with respect to the plate harness and the second molding including the superposed connection of the bus bar and the voltage detection terminal, dimensional control over the shrinkage of molded resin plate can readily be effected.

The step of preparing the primary molded piece preferably further comprises, according to the present invention, molding the direction in which the molten resin is supplied to the primary mold along a direction of wiring the electric wires of the plate harness set in the primary mold.

As a resin skin layer is initially formed on the surface of the electric wire and then high-temperature is thus prevented from being directly brought into contact with the electric wire, it is possible to eliminate the destruction of the electric-wire covering portion by fusing, which results in dispensing with the use of special heat-resistant electric wires covered with polyimide resin as before, thus making cost reduction feasible.

It is also preferred to make the step of preparing the primary molded piece further comprise, according to the present invention, molding an exposed portion in part of the electric wire of the plate harness set in the primary mold.

According to the present invention, dimensional control over the whole connecting plate is facilitated since the partial exposed portions of electric wires can be utilized for dimensional adjustment due to shrinkage of resin and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a battery holder having a connecting plate for a battery holder which is an embodiment of the invention;

FIG. 2 is a perspective view of the connecting plate for a battery holder of FIG. 1;

FIG. 3 is an enlarged perspective view of main portions of the connecting plate of FIG. 2;

FIG. 4 is an enlarged perspective view showing a connecting state of a bus bar, a voltage detection terminal, and a circuit protecting device which are shown in FIG. 3;

FIG. 5(A) is a circuit diagram showing connections of batteries and voltage detection terminals in connecting plates 10 and 10′ of FIG. 1, and

FIG. 5(B) is a circuit diagram showing connections of PTC devices for detecting heat generation in a battery;

FIG. 6 is a view illustrating a production step (pretreatment step) of the connecting plate for a battery holder of FIG. 1;

FIG. 7 is a view illustrating a production step (connection of terminals and fitting to case) subsequent to that of FIG. 6;

FIG. 8 is a view illustrating a production step (a step of wiring a harness for a plat e) subsequent to that of FIG. 7;

FIG. 9 is a view illustrating a production step (a primary molding) subsequent to that of FIG. 8;

FIG. 10 is a perspective view of main portions of a primary molded product obtained in the step of FIG. 9;

FIG. 11 is a view illustrating a production step (a secondary molding) subsequent to that of FIG. 9;

FIG. 12 is a plan view showing a state in which the primary molded product of FIG. 11 i s set in a mold;

FIGS. 13(A) to 13(D) show the final production step (a step of mounting a circuit protecting device), and FIG. 13(A) is a plan view of a window for mounting a circuit protecting device, FIG. 13(B) is a perspective view of the window, FIG. 13(C) is a section view of the window, and FIG. 13(D) is a section view showing a state in which the circuit protecting device is connected;

FIGS. 14(A) and 14(B) show a manner of leading out connecting wires of the connecting plate for a battery holder of FIG. 2, and FIG. 14(A) is a perspective view of main portions of a primary molded product P₁, and FIG. 14(B) is a perspective view of main portions of a secondary molded product P2;

FIGS. 15(A) to 15(B) show another embodiment of the primary molding step of FIG. 9, and FIG. 15(A) is a perspective view of main portions of upper and lower molds using a rubber mat, and FIG. 15(B) is an exploded perspective view of the main portions;

FIG. 16 is a section view showing another embodiment of the rubber mat;

FIGS. 17(A) and 17(B) show a supplementary embodiment of the primary molding step of FIG. 9, and FIG. 17(A) is a perspective view of main portions of an upper (lower) mold using another rubber mat, and FIG. 17(B) is a section view of the main portions;

FIG. 18 shows an another supplementary embodiment of the primary molding step of FIG. 9 and is a view illustrating a method of supplying a resin to molds;

FIGS. 19(A) and 19(B) show main portions and illustrates a structure for connecting the bus bar, the voltage detection terminal, and the circuit protecting device in the connecting plate for a battery holder, and FIG. 19(A) is a perspective view showing the secondary molding, and FIG. 19(b) is a perspective view showing the final step;

FIG. 20(A) is a section view taken along the line X—X of FIG. 19(B), and

FIG. 20(B) is a section view taken along the line Y—Y of FIG. 19(B) and showing a state in which the circuit protecting device is attached;

FIGS. 21(A) and 21(B) are views illustrating another structure for connecting the bus bar, the voltage detection terminal, and the circuit protecting device in the connecting plate for a battery holder;

FIGS. 22(A) and 22(B) show a structure for relaxing stress in the voltage detection terminal of the connecting plate for a battery holder of FIG. 1, and FIG. 22(A) is a perspective view of main portions, and FIG. 22(B) is a section view taken along the line X—X of FIG. 22(A);

FIGS. 23(A) and 23(B) show another structure for relaxing stress in the voltage detection terminal, and FIG. 23(A) is a perspective view of main portions, and FIG. 23(B) is a longitudinal section view;

FIGS. 24(A) to 24(C) show a further structure for relaxing stress in the voltage detection terminal, and FIG. 24(A) is a perspective view of a voltage detection terminal 17′, and FIGS. 24(B) and 24(C) are longitudinal section views respectively showing states of attaching the terminal to window frames 14′ and 14″;

FIG. 25(A) is a perspective view showing main portions of an example of a conventional connecting plate for a battery holder,

FIG. 25(B) is a longitudinal section view of a fuse holder shown in FIG. 25(A);

FIG. 26 is a perspective view showing main portions of another example of a conventional connecting plate for a battery holder;

FIG. 27 is a view showing another example of conventional connecting batteries;

FIG. 28(A) is a diagram illustrating a conventional structure for fixing electric wires and a resin-molded plate together, and

FIG. 28(B) is a diagram illustrating a top and a bottom force; and

FIG. 29 is a diagram illustrating a method of supplying resin in a conventional mold.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the invention will now be described with reference to FIGS. 1 to 24(c).

Referring to FIG. 1, A denotes a long cylindrical battery which is to be used in an electric vehicle or the like, and B denotes a battery holder for housing a large number of batteries A. In each of the batteries A, nut-shaped positive and negative electrodes 2 a and 2 b having a female thread are disposed at the ends of the body 1, respectively. A PTC device 3 is embraced by and fixed to the outer periphery of the body 1 in order to check heat generation of the battery A.

The battery holder B comprises a rectangular frame-like main unit 4, and connecting plates 10 and 10′ which are attached to the sides of the main unit, respectively. In the illustrated example, the frame-like main unit 4 has a frame structure in which plural support plates 6 where are arranged in parallel and in a row by using stays 7. In each of the support plates, eighteen battery insertion holes 5 in total are opened in a matrix of 6 holes in vertical and 3 holes in lateral. Plural bolts 9 for fixing the battery holder to the vehicle body are implanted in one side wall 8 extending in the longitudinal direction.

FIG. 2 is a perspective view of the connecting plate 10, FIG. 3 is an enlarged view of main portions of the plate, and FIG. 4 is a perspective view showing a connecting state of a bus bar, a voltage detection terminal, and a circuit protecting device which are shown in FIG. 3.

The connecting plate 10 (10′) is configured by inserting and fixing bus bars 16 and 16′ (see FIG. 12) connecting the plural batteries, voltage detection terminals 17, fuses 21 serving as circuit protecting devices, connecting wires 22, and the like, into a molded resin board 11.

In the molded resin board 11, hexagonal windows 12 and rectangular windows 12′ for connecting electrodes are formed in accordance with the arrangement of the plural batteries A. A rectangular window 13 for connecting the PTC device is formed at the side of each of the windows 12 and 12′. Two fuse mounting windows 14 are juxtaposed between desired hexagonal and rectangular windows which are denoted by 12 ₁ and 12 ₁′. Connecting pieces 15 for connecting the PTC devices 3 in series are embedded between adjacent rectangular windows 13, and connecting end portions 15 a at the ends and having a connection hole 15 b are exposed through the rectangular windows 13. The fuses 21 are housed in the fuse mounting windows 14, respectively.

Each of the bus bars 16 is formed as a link-like plate member through which a large current can flow. A battery connection hole 16 a is formed at each end. The bus bars are arranged at intervals corresponding to the arrangement of the batteries A. The bus bars 16′ are formed into a U-like shape so as to connect adjacent batteries A in a vertical row.

Among the plural bus bars 16 (16′), for example, bus bars denoted by 16 ₁ are connected to the voltage detection terminals 17, respectively.

Each of the voltage detection terminals 17 (see FIG. 6) comprises an overlap contact portion 18 opposed to the corresponding bus bar 16, a device mounting portion 19 which is continuous to the overlap contact portion, and a wire connecting portion 20. These portions are integrally formed by punching or bending an electrically conductive metal plate.

The overlap contact portion 18 is formed as a square or rectangular plate member of a size which enables the portion to be substantially overlapped to an end portion of the bus bar 16. A bolt insertion hole 18 a having the same diameter as the battery connection hole 16 a is formed in a center portion. Plural (in the illustrated example, four) resin leakage inspection holes 18 b of a small diameter are formed around the hole 18 a. Resin leakage preventing pieces 18 c and 18 c′ which serve also as positioning pieces are downwardly bent and formed in two edges of the overlap contact portion 18 which perpendicularly intersect with each other. When the pieces 18 c and 18 c′ abut against side edges of the end portion of the bus bar 16, the center of the bolt insertion hole 18 a is automatically made coincident with that of the battery connection hole 16 a.

The device mounting portion 19 is continuously formed via a connection piece 18 d which is downward cranked, on the resin leakage preventing piece 18 c′ which is on one of the two adjacent edges of the overlap contact portion 18. The device mounting portion 19 includes a pair of lead connecting pieces 19 a opposed to leads 21 b of the ends of the fuse 21, and a connecting piece 19 b which integrally holds the two connecting pieces. A lead connection hole 19 c is formed in each of the lead connecting pieces 19 a. The device mounting portion 19 is made lower in level than the overlap contact portion 18 by the connection piece 18 d and one of the lead connecting pieces 19 a, and elongates in parallel with the resin leakage preventing piece 18 c′. The wire connecting portion 20 is formed continuously with the other lead connecting piece 19 a. One end of the insulated wire 22 is connected to a pair of a wire barrel 20 a and an insulation barrel 20 b of the wire connecting portion 20, by crimping or the like. The other end side of the wire 22 is laid together with the other wires so as to be led out to one side edge lla of the molded resin board 11. The wires are held at the side edge by a wire holder 23 so as to be arranged at given intervals.

The device mounting portion 19 of the voltage detection terminal 17, i.e., the pair of the lead connecting pieces 19 a and the connecting piece 19 b are exposed through the fuse mounting window 14 of the molded resin board 11. A pair of fuse engaging arms 24 which have at the upper end a hook-like engaging projection 24 a are integrally formed on the inner walls 14 a (see FIG. 13) which are on both the sides of the window and sandwich the connecting piece 19 b, respectively.

After insert molding of the molded resin board 11, the connecting piece 19 b of the device mounting portion 19 is cut away in the fuse mounting window 14. The leads 21 b of the ends of the fuse 21 are respectively passed through the lead connection holes 19 c of the remaining lead connecting pieces 19 a at both the sides, and then applied with solder 25, whereby the fuse 21 is connected and fixed to the voltage detection terminal 17. The fuse 21 the leads of which are passed through the lead connection holes 19 c is clamped by the pair of fuse engaging arms 24, and the hook-like engaging projections 24 a, thereby preventing the fuse from slipping off. Even when the molded resin board 11 is turned upside down, therefore, the fuse is prevented from falling off. Furthermore, a soldering work can be easily conducted.

FIG. 5 is a connection diagram in the case where the batteries A are connected in series by using the connecting plates 10 and 10′, and FIG. 5(A) shows a voltage detection circuit for the batteries and FIG. 5(B) shows a temperature detection circuit for the batteries.

Returning to FIG. 1, the batteries A are inserted into the battery insertion holes 5 of the battery holder B in such a manner that their positive and negative electrodes 2 a and 2 b are alternatively inverted. The connecting plates 10 and 10′ are set on the electrodes 2 a and 2 b protruding from the ends of the holder B, and the ends of the bus bars 16 (16′) are alternatively fastened and fixed to the positive and negative electrodes 2 a or 2 b of the batteries A by the bolts 26.

As a result, as shown in FIG. 5(A), the batteries A₁, A₂, A₃, . . . A_(n) are connected in series by the bus bars 16 (16′). The fuses 21 are connected to ends of single-pole bus bars 16″ and double-pole bus bars 16 via the voltage detection terminals 17. When the wires 22 are connected to an ECU which is not shown, therefore, the voltages of all the batteries A can be always monitored for each sets of two batteries. Batteries A generating an abnormal voltage can be rapidly replaced with other ones in the unit of two batteries.

As described above, the PTC devices 3 are attached to the batteries A₁, A₂, . . . A_(n), respectively. The lead wires (not shown) of the both sides of each PTC device are connected to the ends of the connecting piece 15 in the connecting plate 10 (10′). Specifically, screws which are not shown are fastened to the connection holes 15 b of the connecting end portions 15 a at the ends. On the other hand, the lead wires of the PTC device 3 are led out from through paths 13 a formed in one side of the rectangular windows 13. The lead wires are fixed by the screws.

As a result, as shown in FIG. 5(B), all the PTC devices 3 of the batteries A₁, A₂, . . . , A_(n) are connected in series. When any one of the batteries abnormally generates heat, the resistance of the PTC device 3 corresponding to the battery is suddenly increased, and hence the check circuit is opened.

In this way, the embodiment has a structure in which an abnormal voltage and abnormal heat generation of the batteries A in the batter holder B are always monitored.

Next, a method of producing the connecting plate 10 (10′) will be described with reference to FIGS. 6 to 13.

First, the insulated wires 22 which are to be connected to the voltage detection terminals 17 of the connecting plate 10 are prepared. For the convenience of maintenance and the like, preferably, different colors or markers such as a pattern, a stripe, or a symbol are applied to the insulating coating of the wires 22. The wires are cut into a predetermined length and the coating at each end is peeled off.

Next, as shown in FIG. 6, the exposed core wire 22 a at one end is connected to the wire connecting portion 20 of the voltage detection terminal 17, and a female (or male) connector terminal 30 is connected to the other end, thereby producing a terminal-equipped wire 22′.

As shown in FIG. 7, the connector terminals 30 of the thus prepared terminal-equipped wires 22′ are then inserted into and engaged with a terminal chamber (not shown) of a connector (housing) 31. The engaging structure between the connector terminals and the terminal chamber may be formed in accordance with known means, and hence its illustration is omitted.

Next, as shown in FIG. 8, the voltage detection terminals 17 of the terminal-equipped wires 22′ are arranged on a wiring table 32 in accordance with the arrangement positions of the bus bars 16 (16′) to which the terminal-equipped wires are connected to be overlapped. The wires 22′ connected to the voltage detection terminals 17 are laid so as to be combined in a center portion of the molded resin board 11, in order to lead out the wires from one side edge of the board. The wires are combined into a flat shape by tapes 33 to form a harness 34 for a plate.

The above will be described in more specifically. In the battery holder B of FIG. 1, the number and positions of the battery insertion holes 5 of the support plate 6 are predetermined, and hence also the layout of the bus bars 16 and 16′ in the connecting plate 10 is uniquely determined. In accordance with the layout, therefore, a pair of connector engaging pins 35, and plural pairs of wire engaging pins 36 (36 ₁ to 36 ₃) and terminal engaging pins 37 (37 ₁ to 37 ₃) are retractably disposed on the wiring table 32.

These pins 35, 36, and 37 erect from a mounting base which is not shown, and are caused to collectively protrude from and retract into holes formed in the wiring table 32 by raising and lowering the mounting base.

First, second, and third wire engaging pins 36 ₁, 36 ₂, and 36 ₃ which are respectively paired are linearly arranged at the center of the wiring table 32 with starting from the side closer to the pair of connector engaging pins 35. The terminal engaging pins 37 ₁ to 37 ₃ are arranged so as to sandwich or on both the sides of the pairs of wire engaging pins 36 ₁ to 36 ₃. The gap between the engaging pins 36 ₃ which are remotest from the connector engaging pins 35 is smallest. As a pair of pins are closer to the connector engaging pins 35, the gap between the pins is larger. These gaps respectively form spans in which the wires 22′ laid in the gap can be housed in a substantially flat manner.

In the formation of the harness 34 for a plate, the terminal-equipped wires 22′ (see FIG. 7) which are previously obtained are moved onto the wiring table 32, the back face (the wire connection side) of the connector 31 abuts against the pair of connector engaging pins 35, and the wires 22′ are then arranged between the wire engaging pins 36 ₁, between the pins 36 ₂, and between the pins 36 ₃.

Next, the plural wires 22′ between the wire engaging pins 363 are arranged so that a flat state in which the wires do not overlap nor cross with one another is maintained. The wires are bent at the pins 363 to either side into an L-like shape. The bolt insertion holes 18 a of the overlap contact portions 18 in the voltage detection terminals 17 at the tip end portions of the wires are engaged with the terminal engaging pins 37 ₃, respectively. Thereafter, the flat portions of the wires 22′ are bundled by the tape 33. Also the wires 22′ between the wire engaging pins 36 ₂ and between the pins 36 ₁ are then processed in the same manner.

As a result, as shown in FIG. 8, the harness 34 for a plate is formed in which the connector 31 is attached to the one-end side of the flatly arranged wires 22′, the other-end sides are branched at given intervals by bending into an L-like shape in a bilaterally symmetrical manner by the wire engaging pins 36 and the terminal engaging pins 37, and the voltage detection terminals 17 are connected to the tip ends.

The harness 34 for a plate is detached from the wiring table 32, and, as shown in FIG. 9, then set in a recess 39 of a primary mold 38 to be subjected to the insert molding by a known method (the upper mold corresponding to the mold 38 is not shown), thereby obtaining a primary molded product P₁ shown in FIG. 10.

In the connecting plate 10 of FIG. 2, the dimension X between the outer voltage detection terminals 17 _(o) which are largely separated from each other, the dimension Y between the inner terminals 17 _(i), and the dimension Z between the terminals 17 _(o) which are vertically separated from each other must be correct, and hence severe accuracy is requested. However, it is difficult to perform the insert molding by one step while, from an initial stage, maintaining the accuracy of the dimensions between the many bus bars 16 and 16′ and the wire-equipped voltage detection terminals 17.

As apparent from FIG. 10, the primary molded product P₁ is integrally molded by primary molded res in boards 11A, 11B, 11B′ , 11C, and 11C′ with leaving a part 22A′ of the wires 22′, and the overlap contact portions 18 and the device mounting portions 19 of the voltage detection terminals 17.

Specifically, there exist the wire exposed portions 22A′ among the primary molded resin board 11A in a center portion of the primary molded product P₁, and the primary molded resin boards 11B, 11C, 11B′ , and 11C′ on the lateral sides. Furthermore, there is no tie in the gaps on the lateral sides between the primary molded resin boards 11B and 11C, and 11B′ and 11C′ where the wires 22′ do not exist. The gaps constitute free portions F.

In the primary molded resin board 11A in the center portion, plural pin holes 41 and vertical grooves 42 are formed, and the wire holder 23 is integrally disposed. The pin holes 41 and the vertical grooves 42 are formed by pins and bosses (both are not shown) which protrude into the recess 39 in order to prevent the wires 22′ from, in the insert molding using the primary mold 38, being subjected to an excessive force due to the injection force of the resin, or twined with each other. A wire fixing piece 43 which is indicated by phantom lines is disposed in the mold 38, so that, in the primary insert molding, the wires 22′ on the side of the connector 31 are prevented from being disturbed and stress concentration at the outlet of the wire holder 23 is prevented from occurring.

In the primary molded resin board 11B (11B′), a window frame 14′ for forming a resin non-filled portion, i.e., the fuse mounting window 14 is disposed, two voltage detection terminals 17 _(o) and 17 _(i) are fixed by the insert molding so as to laterally interpose the window frame 14′ therebetween, the overlap contact portions 18 of the two terminals are exposed to the outside, and the device mounting portions 19 are exposed in the window frame 14′.

By contrast, in the primary molded resin board 11C (11C′), laterally arranged voltage detection terminals 17 _(o) and 17 _(i) which are configured in a similar manner as those of the primary molded resin board 11B are vertically arranged, so that three or four terminals in total are fixed by the insert molding.

Any one of the primary molded resin boards 11B 11C of the primary molded product P₁ is configured by fixing two to four voltage detection terminals 17 _(o) and 17 _(i) which are close to each other, by the insert molding. Therefore, the terminals can be fixed with substantially high accuracy of the dimension between the terminals and without being largely affected by the kind of the resin.

In the primary molded product P₁, therefore, the dimensions X′, Y′, and Z′ between various terminals in FIG. 10 may be formed so as to be longer than the dimensions of the connecting plate 10 of the final product of FIG. 2, by using the wire exposed portions 22A′ and the free portions F as dimension adjusting portions, and the dimensions may be finally adjusted in the secondary molding.

Next, as shown in FIGS. 11 and 12, the primary molded product P₁ is set in a secondary mold 45, and a secondary insert molding is then performed.

In a recess 46 of the secondary mold 45, positioning engaging pins 47 and 48 for the bus bars 16 and 16′ and the PTC device connecting pieces 15 are disposed, and collar engaging pins 49 are disposed at the four corners. Moreover, the positioning bosses (not shown) for the pin holes 41 and the vertical grooves 42 of the primary molded product P₁ are disposed. The reference numeral 50 denotes a holder placing groove for the wire holder 23.

The bus bars 16, 16′, and 16″, the connecting pieces 15, and a collar 51 are correctly positioned and engaged by the various engaging pins 47 to 49 in the recess 46. Thereafter, the primary molded resin boards 11A to 11C, 11B′, and 11C′ of the primary molded product P₁ are set, and the positioning of predetermined bus bars 16 and the voltage detection terminals 17 is performed.

The positioning is performed in the following manner. The overlap contact portions 18 of the voltage detection terminals 17 are overlaid on corner portions of the bus bars 16 and 16′ which have been set, so that the resin leakage preventing pieces 18 c and 18 c′ of each of the portions abut against the side edges of the end portion of the corresponding bus bar 16 or 16′ which perpendicularly intersect with each other, as described above (see FIG. 4).

Next, an upper mold (not shown) which is paired with the secondary mold 45 is set on the secondary mold, and the insert molding is then performed under predetermined conditions, thereby obtaining a secondary molded product.

The secondary molded product is different from the completed connecting plate 10 shown in FIG. 2 in that the fuses 21 are not mounted to the fuse mounting windows 14. The illustration of the whole of the secondary molded product is omitted.

Namely, in the secondary molded product, in the same manner as the connecting plate 10, the bus bars 16 and 16′ and the like for connecting the electrodes 2 a and 2 b of the batteries A, and the connecting pieces 15 for connecting the PTC devices are embedded together with the primary molded resin boards 11A to 11C and the like and the free portions F of the primary molded product P₁, into the molded resin board 11. The hexagonal windows 12 and rectangular windows 12′ for connecting the electrodes, and the rectangular windows 13 for connecting the PTC devices are opened. The device mounting portions 19 of the voltage detection terminals 17 are exposed through the fuse mounting windows 14.

When the fuses 21 are mounted to the fuse mounting windows 14 of the secondary molded product, therefore, the connecting plate 10 which is the completed product is obtained.

As shown in FIG. 13(A), in the secondary molded product P₁, the pair of lead connecting pieces 19 a of the device mounting portion 19 are connected to each other by the connecting piece 19 b in the fuse mounting window 14. As shown in FIG. 13(B), the connecting piece 19 b is cut away, the leads 21 a of the fuse 21 are passed through the lead connection holes 19 c of the lead connecting pieces 19 a, and at the same time the fuse body unit 21 a is pressingly inserted between the pair of fuse engaging arms 24.

As a result, as shown in FIG. 13(C), the fuse body unit 21 a is clamped between the engaging arms 24, and the hook-like engaging projections 24 a serve as stoppers. Consequently, the fuse 21 does not vertically slip off and is surely clamped.

Even when the secondary molded product P2 is turned upside down as shown in FIG. 13(D), therefore, there arises no fear that the fuse 21 slips off, and the solder 25 can be applied very easily.

As a result of the above process, the connecting plate 10 (10′) which is the completed product is obtained.

Since the fuse 21 is clamped by the pair of fuse engaging arms 24 so as to be prevented from slipping off, the secondary molded product P2 can be easily stocked and transported.

FIGS. 14(A) and 14(B) show other embodiments of the primary molded product P₁ and the secondary molded product P₂ in which the manner of leading out the connecting wires in the connecting plate is improved.

In the embodiment of FIG. 14(A), the primary molded resin board 11A in the center portion of the primary molded product P₁ is configured so that a fixing frame 51 is formed integrally with one side of the wire holder 23 for binding the wires 22′ and a band 115 (see FIG. 14(B)) for binding the wires 22′ is tied to the fixing frame 51 so as to perform the fixation. According to this configuration, even when an external force acts on the wires 22′, stress concentration at the root portions 22B of the wires can be relaxed or blocked.

During transportation or stock in the process of forming the primary molded product P₁ into the secondary molded product P₂ shown in FIG. 14(B), or after the secondary molding is performed and the molded product is embedded into and protected by the molded resin board 11, therefore, the wires 22′ are effectively prevented from being broken.

FIGS. 15(A) and 15(B) show another embodiment for stress relaxation.

The primary molded product P₁ of FIG. 15(A) is configured so that, in place of the wire holder 23 for bundling the wires 22′ of the primary molded resin board 11A into a flat shape, a pair of upper and lower mats 52 clamp the wires.

In each of the mats 52, plural wire placing grooves 52 b are arranged on one face of a block-like mat body 52 a. Each mat is made of an elastic member having heat resistance, such as silicone rubber. The rear half portions of the mats 52 which vertically clamp the wires 22′ are embedded into the primary molded resin board 11A, and the front half portions protrude from the resin board 11A. Therefore, stress acting on the root portions 22B of the wires 22′ can be absorbed and relaxed.

As shown in FIG. 15(B), a mat receive groove 53 is formed in the inner side of wire placing grooves 38 a of the primary mold 38, and the mats 52 are placed in the mat receive groove. Therefore, the primary molding may be performed by a conventional method.

In the primary molding, the resin which is injected or filled into the primary mold 38 is blocked by the upper and lower mats 52. Therefore, the interface portions (or edges) between the wire placing grooves 38 a can be loosely formed, so that the wires 22′ are prevented from being bit.

FIG. 16 shows another embodiment of the mats for stress relaxation.

In mats 52′ shown in FIG. 16, a large number of projections 52 c are formed in a staggered manner on one face of each of mat bodies 52 a. The projections 52 c may have any one of shapes such as a cylindrical shape, a prism-like shape, and a semispherical shape. Preferably, the projections have a semispherical shape.

The mats 52′ can be used in the primary molding by using the primary mold 38 having the mat receive groove 53 shown in FIG. 15(B), and attain the same effects as that of FIG. 15(A).

FIGS. 17(A) and 17(B) show supplementary embodiments of the mats for stress relaxation and the primary mold.

Referring to FIG. 17(A), in each of upper and lower mats 52″, plural wire placing grooves 52 b are disposed in one face of a mat body 52 a, and a pair of engaging bosses 52 d protrude from the opposite face of the mat body. The engaging bosses 52 d are provided at the tip end with a bulb-like engaging projections 52 d ₁,

In order to comply with the mats 52″, in a primary mold 38′, in place of the wire placing grooves 38 a, plural guide pins 54 are disposed so as to protrude in front and rear of a mat receive groove 53′, and engaging holes 55 corresponding to the engaging bosses 52 d of the mats 52″ are disposed.

In the case of the mats 52″, when the engaging bosses 52 d are strongly pressed against the respective engaging holes 55, the engaging bosses 52 d at the tip end pass through the engaging holes 55 to be engaged therewith as shown in FIG. 17(B). Consequently, there is no fear that the mats 52″ which have been once set slip off. The wires 22′ may be placed so as to separately or one by one pass through between the guide pins 54 which are arranged in front and rear of the mats 52″. As a result, the wires naturally correspond in one to one relationship to the wire placing grooves 52 b of the mats 52″, and hence the work can be simplified.

FIG. 18 shows a method of supplying a resin to molds in the primary molding.

Referring to FIG. 18, a resin filling hole 56 which is directed along the laying direction of the wires 22′ of the harness 34 for a plate (see FIGS. 8 and 9) in the inner side is opened in a side face of the primary mold 38.

The flow of the molten resin injected from a nozzle 119 of a molding machine 118 is directed along the laying direction of the wires 22′ as indicated by the arrow lines. According to this configuration, a resin skin is first formed on the surfaces of the wires 22′, and hence the hot resin does not thereafter make direct contact with the wires 22′. As a result, melt fracture of the wire coating portions is eliminated. Unlike the prior art, therefore, it is not required to use a heat resistant material such as a polyimide resin in the insulation coating of the wires 22 (22′).

FIGS. 19(A) and 19(B) are perspective views of main portions and showing the structure for connecting the bus bar 16, the voltage detection terminal 17, and the fuse 21. FIG. 19(A) shows a state in the secondary molding, and FIG. 19(B) shows that in the final step. FIGS. 20(A) and 20(B) are section views respectively taken along lines X—X and Y—Y of FIG. 19(B). In order to simplify the drawings, the fuse engaging arms 24 are not shown.

Prior to the secondary insert molding, the voltage detection terminal 17 is positioned with respect to the bus bar 16. This positioning can be easily performed because, as described above, the two resin leakage preventing pieces 18 c and 18 c′, which perpendicularly intersect with each other serve as positioning pieces with respect to the bus bar 16.

In the secondary molding, a fear that a molten resin enters between the overlapping faces of the bus bar 16 and the overlap contact portion 18 is substantially eliminated by the blocking function due to the resin leakage preventing piece 18 c or 18 c′ which is positioned in the flow direction of the molten resin. The bus bar and the portion are surely contacted and fixed by mold fixation.

As shown in FIG. 20(A), even when a molten resin 57 enters between the bus bar 16 and the overlap contact portion 18, the entrance can be easily checked through the resin leakage inspection holes 18 b, whereby a defective product and a failure in the flow can be prevented from occurring.

A secondary molded product P2 which is checked that the resin leakage does not occur in the secondary insert molding is processed in the following manner. In the fuse mounting window 14, the connecting piece 19 b of the device mounting portion 19 is cut away as shown in FIG. 19(B). The leads 21 a of the fuse 21 are passed through the lead connection holes 19 c of the remaining lead connecting pieces 19 a at the ends, and then applied with solder 25 as shown in FIG. 20(B).

As seen from the comparison of FIGS. 19(B) and 19(A), the lead connecting pieces to which the leads 21 a at the ends of the fuse 21 are to be connected, i.e., the lead connecting piece 19 a on the side of the overlap contact portion 18, and the lead connecting piece 19 a on the side of the wire connecting portion 20 are initially connected to each other through the connecting piece 19 b. In the primary and secondary moldings, therefore, the parts such as the overlap contact portion 18, the device mounting portion 19, and the wire connecting portion 20 can be collectively handled as a single part, i.e., the voltage detection terminal 17. As a result, the number of parts and the man-hour can be reduced, and the production cost can be lowered.

FIGS. 21(A) and 21(B) show other embodiments of the resin leakage inspection holes of the overlap contact portion, respectively.

The resin leakage inspection holes 18 b′ of FIG. 21(A) are formed as quadrant-like slits which are very larger in size than the resin leakage inspection holes 18 b. The four holes are symmetrically disposed around the bolt insertion hole 18 a. The resin leakage inspection holes 18 b′ are positioned diametrically outside a dish portion 26 a of the bolt 26.

In the embodiment shown in FIG. 21(B), the overlap contact portion 18′ is formed into a doughnut-like disk shape, and the spaces between the round outer peripheral edge 18 e and the inner edge of the rectangular hole 12′ are used as resin leakage inspection holes 18 b″.

Both the resin leakage inspection holes 18′ and 18 b″ have an area which is very larger than the area of the resin leakage inspection holes 18 b, and look like a window.

In the case where a large hole (or a window) such as the resin leakage inspection holes 18′ or 18 b″ is formed, when the molten resin injected into the molds in the insert molding reaches the inspection holes 18′ or 18 b″, the resin is abruptly released and its pressure is lowered. This perfectly prevents the resin from entering toward the center portion (i.e., the bolt insertion hole 18 a), thereby eliminating a failure of continuity between the bus bar 16 and the voltage detection terminal 17.

Returning to FIG. 20(B), in the connecting plate 10, the whole of the parts (the lead connecting pieces 19 a at the sides, the wire connecting portion 20, and the like) to which the fuse 21 is connected are bound by the molded resin board 11. When an external force such as an impact or a pressing force is applied to a part of the connecting plate 10, therefore, stress propagates via the resin board 11 to reach the connection portions such as the solder 25, thereby producing a danger that a trouble such as a crack of the solder occurs.

FIG. 22 shows a structure for relaxing such stress. FIG. 22(A) is a perspective view of the fuse mounting window 14, and FIG. 22(B) is a longitudinal section view taken along the line X—X of FIG. 22(A).

Rectangular slits 58 are disposed around the whole periphery of the window frame 14′ of the primary molded resin board 11B (11C) in the primary molded product P₁. The reference numeral 58 a denotes ties (in the illustrated example, four ties) corresponding to spouts for a resin in the molding of the window frame 14′. A middle portion of each of the lead connecting pieces 19 a at the ends of the device mounting portion 19 in the voltage detection terminal 17 is located in one of the slits 58.

Even when an external force acts on the primary molded product P₁ (or the secondary molded product P₂), therefore, stress due to the force is interrupted by the slit 58, and the window frame 14′ and the internal parts such as the solder 25 are not affected by the stress.

Referring to FIG. 22(A), in order to eliminate the ties 58, the resin filling hole (see FIG. 18) in the molds may be disposed for each of the whole of the molds and the formation of the window frame. According to this configuration, the window frame 14′ has a floating island of a certain kind which is supported by the lead connecting pieces 19 a at both the sides, and hence the solder 25 inside the frame is perfectly unaffected by the outside.

FIGS. 23(A) and 23(B) show another embodiment of the structure for relaxing stress. FIG. 23(B) is a section view taken along the line X—X of FIG. 23(A).

A window frame 14″ is pre-inserted aside from the primary molding (see FIGS. 9 and 10) of the harness 34 for a plate.

The pre-insert may be previously prepared by using the voltage detection terminal 17 having the device mounting portion 19. Therefore, the primarymolding (main insert) may be performed by using the window frame 14″.

According to this configuration, an interface 59 is formed between the resin portion (the window frame 14″) of the pre-insert and that (the primary molded resin board 11B, 11C) of the main insert. Even when bending stress or the like is applied, therefore, a gap is formed in the portion and the propagation of the stress is suppressed. The resin materials of the pre-insert and the main insert may be identical with or different from each other. From the view point of enhancement of the suppression effect, it is preferable to use different materials.

FIGS. 24(A) to 24(C) show another embodiment of the structure for relaxing stress. FIG. 24(A) is a perspective view of a voltage detection terminal, FIG. 24(B) is a section view showing a state of attaching the terminal to the window frame 14′ of FIG. 22(A), and FIG. 24(C) is a section view showing a state of attaching the terminal to the window frame 14″ of FIG. 22(B).

The voltage detection terminal 17′ shown in FIG. 24(A) is different from the voltage detection terminal 17 in that a second connection piece 18 d′ which is upward cranked is disposed between the device mounting portion 19 and the wire connecting portion 20, and that, as a result of this disposition, the center axis of the wire connecting portion 20 is in a plane which is substantially flush with the overlap contact portion 18.

As shown in FIG. 24(B), the bent portion serving as the second connection piece 18 d′ is located in the slit 58 in the outer periphery of the window frame 14′. Alternatively, as shown in FIG. 24(C), the bent portion is located at the interface 59 between the window frame 14″ of the pre-insert and the primary molded resin board 11B and the like of the main insert.

In the case of FIG. 24(B), the existence of the slit 58 and the bent portion surely blocks the transmission of stress to the lead connecting piece 19 a in the window frame 14′.

In the case of FIG. 24(C), the window frame 14″ of the pre-insert can be moved (or slid) together with the fuse 21 inside the frame, and this portion can similarly block the transmission of stress.

As set forth above, according to the present invention, the following effect is achievable.

A connecting plate for a battery holder of an easy-to-fabricate, safety structure can be provided wherein the battery-to-battery connecting bus bars and the voltage detection terminals forming voltage detection circuits are resin-molded integrally by insert molding so as to decrease the number of parts exposed outside.

It is possible to provide such a connecting plate for a battery holder as has a smaller number of component parts and connections and offers excellent reliability of electrical connections and is unlikely to produce errors in battery-to-battery connection and wiring.

Furthermore, it is also possible to provide a connecting plate so structured as to prevent stress from being concentrated in a portion where resin-molded connecting electric wires by insert molding are drawn outside.

Since the bus bars, voltage detection terminals, connecting electric wires and the like are formed by insert molding through two steps; namely, the primary molding with respect to the plate harness and the second molding including the superposed connection of the bus bar and the voltage detection terminal, dimensional control over the shrinkage of molded resin plate can readily be effected.

A low-cost connecting plate is producible as it is capable of using ordinary electric wires covered with polyvinyl chloride or polyethylene in place of special heat-resistant electric wires covered with polyimide resin. moreover, dimensional control over the whole connecting plate is facilitated since the partial exposed portions of electric wires can be utilized for dimensional adjustment due to shrinkage of resin and the like.

While there has been described in connection with the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is aimed, therefore, to cover in the appended claim all such changes and modifications as fall within the true spirit and scope of the invention. 

What is claimed is:
 1. A method of producing a connecting plate for a battery holder including a plurality of bus bars each for connecting a plurality of batteries, a molded resin plate in which said plurality of bus bars are integrally molded at intervals corresponding to an arrangement of the plurality of batteries installed in said battery holder, and voltage detection terminal incorporated in said molded resin plate for detecting voltage of a desired one of said batteries in such a condition as to be connected to the bus bars, said method comprising the steps of: a) preparing terminal-equipped electric wires by connecting the voltage detection terminal to one end of each of a plurality of electric wires; b) arranging the voltage detection terminals of the plurality of terminal-equipped electric wires in conformity with the arranging positions of the bus bars to be superposed and connected, wiring a group of electric wires connected to the respective voltage detection terminals so as to be drawn from one side edge of the molded resin plate, and binding the electric wires to form a plate harness; c) preparing a primary molded piece by setting the plate harness thus formed to a primary mold and integrally res in-molding the plate harness excluding the superposed contact portion of the voltage detection terminal; and d) preparing a secondary molded piece by setting the primary molded piece to a second mold, superposing the superposed contact portion of the voltage detection terminal properly on the battery-electrode connecting hole of the bus bars, and integrally resin-molding the superposed combination.
 2. A method of producing a connecting plate for a battery holder as claimed in claim 1, wherein the step of preparing the primary molded piece further comprising the step of: molding the direction in which the molten resin is supplied to the primary mold along a direction of wiring the electric wires of the plate harness set in the primary mold.
 3. A method of producing a connecting plate for a battery holder as claimed in claim 2, in which the step of preparing the primary molded piece further comprises the steps of: molding an exposed portion in part of the electric wire of the plate harness set in the primary mold. 